This invention relates to structural sandwich panels, specifically features and structural members integrated into structural sandwich panels used for structure, support, alignment, and joining. In recent years, with the application of new technology and materials, many products have been introduced to compete with conventional stick building methods in residential and light commercial building construction. New products aspire to add new materials, features not before available, to be more efficient in use, and to be more cost effective than conventional methods. Fluctuations in availability and supply, quality standards, and stable cost of dimensional lumber used for framing material and availability of skilled labor are major factors leading to the introduction of alternative building materials. Of specific interest is the development of new methods and materials for use in building panel components; more specifically structural sandwich panels (SSP) and structural insulated panels (SIP). Recently, structural insulated panels have become a recognized method of construction in residential and light commercial buildings.
A structural sandwich panel is an assembly consisting of a lightweight core adhered between two relatively thin, strong facing sheets. The facing sheets typically are metal, plywood, oriented strand board (OSB) or other lightweight material. The core typically are expanded polystyrene foam, rigid urethane foam, injected urethane foam, paper honeycomb or other semi-rigid types.
Performance of structural sandwich panels are dependent on the assembly acting as a complete system. Axial forces in a structural sandwich panel are carried by compression in the sheets, stabilized by the core material against buckling. Bending moments are resisted by an internal couple composed of forces in the facing sheets. Shearing forces are resisted by the core.
The manufacture of structural sandwich panels using expanded polystyrene foam (EPS), rigid urethane or paper honeycomb core type materials differ from injected urethane foam core method.
Expanded polystyrene, rigid urethane, and paper honeycomb type panels are manufactured by utilizing a precut rigid core material which is placed between a first and second facing sheet and joined with adhesive to the contacting side of the facing sheets. Pressure is applied to the surface of the assembly to obtain an acceptable adhesive bond between the rigid core and first and second facing sheets.
Injected cured foamed urethane core panels are manufactured utilizing containment forms along all outside surfaces of the panel assembly. The containment form holds the first and second facing sheets in position and contain the cured foamed urethane core as it is inserted between the facing sheets. Two part liquid thermosetting resin foam, usually urethane, is mixed and injected into the void between the first and second facing sheets where it expands and cures into a rigid core. The thermosetting resin foam chemically reacts to produce heat and pressure which expands and cures to fill the cavity with a rigid urethane foam core. The edges are formed against the containment forms. The profile of a containment form is transferred to the rigid cured foamed core. Manufacturing by injecting a rigid cured foam urethane core requires a substantial manufacturing containment device, commonly called a fixture. The fixture contains the first and second facing sheets and all edges by exerting pressure on the containment form and the structural sandwich panel assembly sufficient to resist the pressures developed by the expanding urethane foam core during the chemical reaction process.
Structural sandwich panels are typically joined by a groove cut into the core material and fitted with a spline at the joining edges. The spline is secured to the first and second facing sheets with nails or screws. In some cases, when employing urethane core, adjoining panels are joined by means of a molded joint formed by the shape of the containment form. Currently, both methods of manufacture require additional exterior and interior facing material to reach finished condition when used as building panels.
The current methods of manufacturing structural sandwich panels are unsatisfactory as the invention utilizes finished exterior and interior facings to develop the strength for use in residential and commercial buildings and reduces the amount of labor the builder employs to install the necessary exterior and interior finish materials. Additionally, the invention significantly reduces the assembly time necessary to complete a finished wall, floor or roof system and uses less material to achieve superior results.
Another problem with current techniques employed in manufacturing structural sandwich panel products is the incorporation of headers and plates to distribute loads imposed by concentrated weights over windows, doors, and the like. In addition, when a dense material is allowed to bridge between the first and second facing sheets, thermo-wicking is evident through the panel. Thermo-wicking reduces insulation qualities of the panel by allowing heat transfer at the contact points. The invention places rigid structural members and rigid structural headers in a position to allow a thermo break between the first and second facing sheets.
The present invention relates to a method and system of manufacture, assembly, and construction of structural sandwich panels enabling the more efficient use of standard materials commonly used in the construction industry and incorporating additional features currently not found in the structural sandwich panel products. The present invention also relates to the increased energy savings by the use of high insulation values of cured foam urethane core. The present invention also related to the use of cured foam urethane core to bond to the structural members and embedded them into the structural sandwich panel. Integrating rigid structural members into the manufactured structural sandwich panel will increase structural strength of the panel assembly. In addition, integrating rigid structural members in the structural sandwich panel will supplement the requirement of individual panel facings to carry structural loads imposed on the panel assembly. The resultant savings are realized from eliminating application of secondary finish facings sheets to either the interior or exterior surfaces of structural sandwich panels. The invention relates to the incorporation of rigid structural members contained within the panel assembly to allow the use of finished panel material in the manufacture of the structural sandwich panel assembly.
The invention also relates to the manufacturer of 90 degree comer and variable angle structural sandwich panels as a single structural unit. The comer and angle structural sandwich panel provides positive control at angle transitions and increase strength of critical components that are inherently weak and join at high stress points. The invention also relates to the use of rigid structural member and elongated recess to form and function as a joint for abutting structural sandwich panel. The joining method permit adjoining structural sandwich panels to align and lock firmly in place and provide a joining method that will be structurally sound and protective of the panel during shipment. The invention relates to the use of a containment form at edges of the panel to form the elongated recess for mating the rigid structural member and other edge profiles as required. The invention also relates to incorporation of structural fabricated truss member into the structural sandwich panel cavity to increase the load capability of the panel assembly. The utilization of a structural fabricated truss member would increase the strength of the structural sandwich panel assembly and decrease the dependence of external beams and trusses the support of roof and floor structural sandwich panels. Roof and floor structural sandwich panels having rigid structural members at the edges and structural fabricated truss members integral to the interior of the assembly will allow the use of finished facing materials eliminating the application of a secondary facing to finish the panel assembly.
It is an object of the invention to provide a unique structural sandwich panel for use handling structures and the like, which panel provides high strength, positive joining, high insulation values, greater utilization of material, reduced labor, and lower application cost.
It is another object of the invention to provide structural bearing points at the joining edge of abutting panels by the inclusion of foamed-in-place rigid structural member which provide support for loads imposed by mating components and other conditions. The rigid structural member at the edge of the structural sandwich panel provides a male spine for joining the panel to the abutting panel. An elongated recess on the edge of the structural sandwich panel is formed by transferring the profile of the containment form to the cured foam resin core during manufacture. The elongated recess accepts the rigid structural member of the abutting structural sandwich panel to form a positive joint. Positioned placement of the rigid structural member provide for a thermo break between the first and second facing sheets and eliminate thermo-wicking at the joints. All the above features are heretofore unavailable.
It is another object of the invention to provide to embody a single assembly ninety degree (90 degree) comer structural sandwich panel containing a comer rigid structural member assembly. The comer rigid structural member is a load bearing assembly adhered by the cured foam resin core at the angle point, features heretofore unavailable.
It is another object of the invention to provide a single assembly angled structural sandwich panel containing a comer rigid structural member assembly. The comer rigid structural member is a load bearing assembly adhered by the cured foam resin core at the angle point, features heretofore unavailable.
It is another object of the invention to provide to incorporate a rigid structural header in the cured foam resin core of the structural sandwich panel to distribute loads, provide structural strength, and to increase the construction efficiency in a manner and to a degree not heretofore available.
According to yet another preferred embodiment of the invention to incorporate a fabricated wire truss assembly in the cured foam resin core of the structural sandwich panel to provide additional strength and structural load carrying ability, features heretofore unavailable.
Structural sandwich panels are produced in controlled manufacturing environment to maintain a uniform product and allow extensive modification. The incorporation of rigid structural members and assemblies in the structural sandwich panel will allow the use of facing sheet material not currently utilized. The incorporation of rigid structural members positioned to mate with elongated recesses will form a thermo break joint with alignment and structural properties. The structural sandwich panel resulting from the invention will result in higher strength, better material utilization, high insulation values, decreased cost, increased flexibility, and decreased construction time. The attributes of panel construction allow the construction of a closed in, weather tight shell buildings, substantially finished on the first and second facings, in days instead of weeks.